Táng statesman, military commissioner, and historiographer; native of Wànnián 萬年 in the Capital Region of Cháng’ān. Of the prominent Dù lineage, he entered office through hereditary privilege as administrator of Jǐnán 濟南 and rose through prefectural and circuit posts—most notably as financial secretary and military commissioner of Huáinán 淮南—to become Grand Councilor (Tóng Zhōngshū Ménxià Píngzhāngshì) three times. He was canonized Tàibǎo 太保 on retirement and posthumously titled Ānjiǎn 安簡. Beyond his bureaucratic career he was the principal architect of Táng administrative thought, expanding Liú Zhì’s 劉秩 lost Zhèngdiǎn 政典 into the Tōngdiǎn 通典 (KR2m0001)—the foundational work of the zhèngshū genre—begun while in Huáinán c. 766 and presented to the throne in 801. He is the grandfather of the Late-Táng poet Dù Mù 杜牧.